1. Field of the Invention
The invention concerns apparatus and a method for the determination of influenza neuraminidase.
In the fight against influenza one of the most important laboratory tasks is to follow as accurately and as quickly as possible the constant changes of the surface proteins of the influenza virus. Only with the knowledge of these changes is it possible to prepare effective vaccines and to obtain information regarding the state of the protection of the population against influenza.
2. Description of the Prior Art
For the laboratory testing of one of the two surface proteins, i.e. antigens, the so-called haemogglutinin, a micro-method is used. The testing of the other important surface antigen, the so-called neuraminidase enzyme, is cumbersome and involves the use of a complicated test tube system.
The essence of such methods is based on the fact that the enzyme of the surface antigen of the virus is suitable for the release of N-acetyl neuraminic acid (NANA) from mucoprotein and can be determined colorimetrically by means of suitable reagents. From the activity of the enzyme conclusions can be drawn, on the one hand, about the characteristics of the surface antigen of the virus, and on the other hand, by inhibiting the enzymes with specific antibodies, about the affinities or relationships among the viruses and the specificity of the antibodies. The existing test tube method is cumbersome and complicated because the colour reaction takes place only at a specific temperature (90.degree.-95.degree. C) and is stable only at this temperature. Since in such circumstances colorimetric measurement is unsuitable, the colouring material must be extracted with butanol and then centrifuged; but even in this case the measurement or determination must be carried out rapidly because the colour reaction may change in the meantime. The individual handling of the test tubes and the determination of colour intensity by a spectrophotometer is so cumbersome that it is practically impossible to use this method for mass investigation purposes. Nevertheless, there is a distinct need for such mass investigations not only to make comparisons between the different viruses but also, mainly and for the determination of the state of the protection of the population against influenza.